1. Field of the Invention
The present invention relates to a threedimensional display apparatus for reproducing a stereoscopic view. In particular, the present invention relates to a three-dimensional display apparatus which does not require an observer to use viewing aids such as a pair of special purpose spectacles.
2. Description of the Related Art
A three-dimensional display apparatus in a binocular parallax mode (parallax barrier mode) is conventionally used as a three-dimensional display apparatus which allows an observer to view a stereoscopic image without viewing aids such as a pair of spectacles. Such a three-dimensional display apparatus is described in, for example, "THE JOURNAL OF THE INSTITUTE OF ELECTRONICS, INFORMATION AND COMMUNICATION ENGINEERS" C-II, Vol. J76-C-II, No. 1, pp. 16-23, January 1993.
FIG. 25 shows the basic structure of a display section in a three-dimensional display apparatus in a conventional parallax barrier mode. A display section 110 includes an image display panel 101 and a slit array panel 102 which is disposed in front of the image display panel 101. As shown in FIG. 27, the slit array panel 102 includes a plurality of strip-shaped non-transparent portions 105 and a plurality of strip-shaped transparent portions 106 which are alternately disposed at a pitch T. In the case where double-window display is performed, a plurality of strip-shaped images for the left eye (L) and a plurality of strip-shaped images for the right eye (R) are alternately disposed on the image display panel 101 at a pitch V as shown in FIG. 26. The pitch V of the strip-shaped images is set to be slightly larger than the slit pitch T shown in FIG. 27. Such a configuration enables the stereoscopic view. More specifically, as shown in FIG. 28, the strip-shaped images for the left eye (L) and the strip-shaped images for the right eye (R) displayed on the image display panel 101 are separated through the slit array panel 102 disposed in front of the image display panel 101 so as to be converged to two different spacial positions. Therefore, by setting the left eye 103 and the right eye 104 of an observer to the positions to which images are converged, the observer can observe a stereoscopic image. The positions of both eyes, i.e., a viewing region, are determined in accordance with the relationship between the slit pitch T and the pitch V of the strip-shaped images.
The aforementioned three-dimensional display apparatus in the conventional parallax barrier mode and another conventional three-dimensional display apparatus in a parallax image mode have an extremely narrow viewing region since light beams are converged to the positions of right and left eyes. In particular, since images at a plurality of viewing points are displayed on one image display panel in the three-dimensional display apparatus in a parallax barrier mode, the resolution of a reproduced image in a horizontal direction is deteriorated. The resolution in the horizontal direction is reduced to be half in a stereoscopic mode and to be one-third in a three views mode, as compared with that of a normal two-dimensional reproduced image. In addition, the slit array panel itself obstructs observation of images.